Extreme potassium deficiency in cotton fields will cause a large number of dead trees.

Cotton is sensitive to potassium deficiency, especially since BT transgenic cotton was developed, potassium deficiency cotton fields often showed serious diseases, premature senescence, few bolls and small bolls, poor boll opening and poor fiber quality. Four or five years ago, the results of rapid determination of available nutrients in cotton field soils in central and southern Hebei showed that most of the available potassium contents in soils were less than 80PPM(mg/kg), belonging to serious potassium deficiency, and some soils were less than 40PPM, reaching the degree of extreme potassium deficiency. The data measured by soil nutrient rapid tester are not accurate. Some soil samples measured the available potassium content as 0, which has occurred in many test points, showing the serious degree of potassium deficiency.

Due to the advocacy and practice of increasing potassium fertilizer application, cotton farmers who applied potassium fertilizer and cotton formula fertilizer with high potassium content increased year by year, which played a role in disease control and yield increase, and the content of available potassium in soil also had recovery improvement. However, some cotton farmers had misunderstanding and thought that multiple fertilizer application (Most of the nitrogen, phosphorus, potassium ratio of 1:1:1) containing potassium can replace the application of potassium fertilizer, or with nitrogen, phosphorus, potassium each 19% high concentration compound fertilizer instead of more potassium fertilizer, there are cotton farmers mistakenly think that "potassium sulfate compound fertilizer" is potassium fertilizer, the result is not less money spent but did not play a role in potassium supplementation.

Recently, there has been more rain in the north and the temperature has dropped. Some cotton farmers reflect that some cotton fields are yellow and withered, and even begin to die, and some think it is Verticillium wilt outbreak. The most important basis for judging whether or not the wilt is culm dissection. As long as the xylem of cotton culms does not turn brown, the wilt can be eliminated. The cotton field is likely to be caused by extreme potassium deficiency (potassium deficiency will also induce disease and aggravate the disease). The cotton plants with many peaches in low-lying places, accumulated water places and the whole field are seriously damaged and died. The author has seen such cotton fields every year; and the cotton fields with increased potassium fertilizer will not produce or die in large numbers in the later stage.

Why do some corn stubble cotton fields also die in large numbers? Because corn is a crop that needs more potassium and has strong ability to absorb potassium, if the corn field contains less potassium and the corn yield is high, the available potassium in the soil is almost consumed by corn. If potassium fertilizer is not increased after planting cotton, a large number of dead trees will also be caused. This lesson is quite a lot.

Cotton plants began to show potassium deficiency from early august, the lower part of the old leaves began, heavy rain, and set up more bolls, then continuous spraying 3 times potassium fertilizer will not cause a large number of late dead trees. In the middle of August, if some cotton plants show potassium deficiency, but there are green leaves in the upper part, potassium supplementation can also reduce losses. If the upper leaves of cotton plants are withered now, most of the cotton plants have withered, and it is too late to supplement potassium.